Is "natural" herd immunity for Covid even possible?

[PontiusPrimate]

This is an interesting discussion on an unfortunate experiment in Manaus in Brazil where the virus was able to rampage through the population. What were the main results?

1 - despite an estimated 76% of all people in Manaus getting infected with SC2, no herd immunity was ever measured. The virus continues to rampage through there.

2 - Despite a much younger population than (say) the UK, Manaus had recorded a death rate of 1200 - 1700 deaths per million people. This worked out to an IFR of 0.17-0.28, even for a young and healthy population.

3 - it’s not clear whether herd immunity failed due to not enough people being infected (so it would have to be 80% or even higher?) OR whether people lost their immunity over time and could get reinfected

4 - There was almost zero pre-existing immunity to Covid in the population - throwing the T-cell immunity into doubt. Apparently everyone in Manaus was susceptible, no one had pre-existing immunity despite whatever exposure they had to previous coronaviruses.

5 - The measured seroprevalence was roughly even in every age group and between high risk groups and low risk groups. I’m not sure what measures they took to try and protect the vulnerable, but whatever they were, they completely failed.

6 - In the UK we have officially recorded 3.26 million cases. Let’s assume we are way off, and that the number is closer to 15 million people. That still equals about 23%. If the Manaus data is correct, then we would need nearly 3-4 times this number so perhaps 50-60 million people to become infected and then recover (hopefully!)

And a final note - if the Manaus data is correct, and we apply it to the UK, then to reach some kind of herd immunity (if we even can get there!) we are looking at a death toll of more than 350,000 people. The US would have to have more than 1.6 million deaths. That’s if it’s even possible to reach herd immunity naturally.

Now, I know that the name Neil Ferguson is often used as an insult in certain covid-sceptical circles, but what were his predictions back in March 2020 - before the first wave even hit? His predictions were that to achieve herd immunity by letting the virus sweep through the country, the UK could expect something like 500,000 deaths and the US could expect just over 2.2 million deaths.

I have to say that by the looks of it, Neil Ferguson and his much maligned models were actually spot on. Go figure.

Here is the article

Herd immunity by infection is not an option

and here is the final paragraph

What the findings of Buss et al. definitively show is that pursuing herd immunity through naturally acquired infection is not a strategy that can be considered. Achieving herd immunity through infection will be very costly in terms of mortality and morbidity, with little guarantee of success. Although the duration and effectiveness of immunity in reducing transmission with vaccination is unclear, experience across several infectious diseases suggests that immunity can be boosted safely through vaccination, if required. Even a mitigation strategy whereby the virus is allowed to spread through the population with the objective of keeping admissions just below health care capacity, as is done for influenza virus, is clearly misguided for SARS-CoV-2. Like SARS-CoV and MERS-CoV, this virus is optimally addressed with an aggressive suppression strategy (15). Governments need to focus on more precise NPIs, robust test/trace/isolate systems, border control measures, mass testing, better treatments, and development and delivery of vaccines (15). This is the most sustainable path for countries out of this pandemic.

[RhisiartGwilym]

Sounds exactly like ‘Covid scam - episode nine’ to me. What a strange virus, that doesn’t do what all the others do. Maybe it really is a Fort Detrick creation, gof-ed into complete uniqueness. Or maybe this story is just the latest up-the-ante fake-scare of the scam. How are we to tell…?

The situation is getting so bizarre that you could really believe that even such as the ‘Science’ crew had all in-grouped themselves into believing all this stuff. There appears to be a lot of that about.

Maybe Manaus should go for the DWSNBN1 or DWSNBN2 options, and just cure everyone outright. They could, after all, if they let sanity prevail.

[PontiusPrimate]

Could be an almighty scam. It could be a lab created franken-virus, or it could be that we just don’t understand Corona viruses. Consider:

• There are no vaccines for any Corona viruses prior to this one.

• There is no herd immunity for the common cold (at least one type is Corona)

And yet for this Corona virus we are hoping that a vaccine will lead to herd immunity. Or worse, that we get there “naturally”

I’m far from convinced about any of this…

@RhisiartGwilym

Maybe Manaus should go for the DWSNBN1 or DWSNBN2 options, and just cure everyone outright. They could, after all, if they let sanity prevail.

100% agree. The question was really about the possibility of herd immunity though

[RhisiartGwilym]

No herd immunity for the common cold, P? Why do you say that? Surely that’s a classic case of HI, isn’t it? An endemic nuisance, but which kills virtually no-one. Just a constantly-present small inconvenience. Like every other species, we strike a liveable balance with the micro-organism (if that’s what it is; the ‘no such thing as germs’ concept is doing the rounds again, as you will have noticed, I dare say). The two life-forms then co-exist in a sort of uneasy symbiosis, until the rough edges of the relationship are worn off, and a new - more integrated? - relationship emerges, Lynn Margulis-style.

I confess, I find all previously-held concepts of what goes on in this process have been thrown up in the air for me, as a result of this weird incident of the covid thing.

And have you noticed also that this other weird thing has emerged too: There are two somewhat mutually exclusive - though not entirely so - explanatory hypotheses about what’s happening. In both cases a somewhat nasty novel pathogen seems to be involved, But in one story, it’s a terrifying killer, and governments, etc., all over the world are thrashing about clumsily, but in good faith, to try to contain and overcome it; and in the other story, it’s a handy - but not particularly deadly - novel ill, which is being instrumentalised for prior-existing nefarious purposes. Not exactly with a huge global conspiracy, which seems vanishingly unlikely; but with something even weirder, which seems to have the same practical upshot as a global conspiracy, but is actually an entire global class layer - the careerist technocrats - entering a state of tacitly-agreed hypnosis, that doesn’t actually rise to the level of conscious awareness. A sort of nod-and-wink understanding amongst the technocrats that this crisis offers a ‘heaven’ sent opportunity to make some crucial changes which have been pending, ever more pressingly, for some time. Changes forced on humankind by the steadily more imperative demands of the Long Descent, particularly by one of the LD’s ingredients: out current population-overshoot excursion.

I confess, P, that I really have no idea which of these hypotheses is actually correct; or whether there’s some other more accurate hypothesis. Open-minded scepticism, plus wait-and-see patience seems to be the only practical response, just now. That and stocking up with what we dissidents understand perfectly well by now are the genuinely-effective diy treatments for the new illness: the various DWSNBNs. Thanks to Chris M for that droll coinage!

[PontiusPrimate]

Good points there bwana. Perhaps the problem is that I’m not really understanding what herd immunity really means. Years ago, when I was studying the mathematics of epidemics, I learned that herd immunity means that the pathogen can no longer spread through a population because there are not enough people who are susceptible. So the pathogen dies out. Smallpox is a classic example.

However there is another concept that you rightly point out - as people’s innate defences get exposed to the virus, it can still infect them but does less and less harm. HIV in Kenya is a more modern example of that. I don’t think of this as herd immunity though. That could very well be my own misunderstanding.

When talking about the common cold, I was talking about the first definition. It’s possible for people to get reinfected with the virus - it doesn’t just die out. It very well may be the case that over time and multiple waves of exposure SC2 will also be less and less of a problem until it basically becomes a new type of cold. I guess that no one knows how long or how many waves of infection that process would take.

I think your two narrative description is spot on. I think there is no doubt that the narrative has been hijacked to promote a set of agendas. The HCQ and ivermectin stories are already enough to know that we’re not super interested actual solutions. Additionally, the fact that eminently workable, sensible and affordable guidance from the Indy SAGE folk (hardly fringe lunatics!) is completely ignored in favour of horrendously draconian, expensive, and possibly ineffective actions can’t only be incompetence. And it’s a pattern we see across the neoliberal world.

As the months pass, I find myself increasingly moving to your way of thinking. This is a moderately dangerous illness that could have been entirely managed using existing, well known, well tested public health measures and very safe drugs, but it was fanned into a full blown crisis. And the gov can conveniently point to the populace when they are looking for someone to blame. “Air bridges” and “eat out to help out” are far more significant problems than a handful of “bad egg lockdown rebels” cheekily refusing to follow the ever more bizarre rules.

I don’t particularly doubt the numbers or the death toll, but I 100% doubt the narrative that is being spun around the whole business.

There is no need for any of this, except that some people are getting filthy rich, and we are all being marched into a bright new hyper-controlled dystopian future.

Ok… Deep breath. Rant over

[RhisiartGwilym]

Ah right! Yes, two different definitions of HI. The common cold certainly hasn’t died out for lack of hosts. So it seems that another way of looking at HI is that pathogen and host strike a liveable, symbiotic balance. Neither kills off the other entirely; both can tolerate the deal: Precisely the sort of draw situation which Lynn Margulis was proposing when she was working up her innovative symbiosis ideas in the field of evolutionary genetics of cells, and indeed of all micro-organisms. In a nutshell, we all shuffle about a bit as we run into each other, knocking off corners as we do, but all eventually continue to flow along together in the great unitary flow of life on Earth. The wonderfully-adaptive survivability of the whole life-web keeps it all going.

And thus Mam Gaia’s living Earth continues to be a holodeck virtual-reality playground for the Individuated Units of Consciousness of Big Mind - or individual souls - to play in and grow steadily towards harmonious low entropy, life after life… (Beatific, rapturous grin!) Here endeth the lesson, dearly beloved…

[Evvy_dense]

Great discussion on a thorny addition to an already thorny-enough topic!
Doubt I’ll be able to remove many thorns though…

There is a lot of talk about Herd Immunity but not much about immunity - a kind of hijacking of the innate immune systems which are required to fight these infections, naturally without getting the credit. (It’s The Vaccine ™ that’s going to save us!) These immune systems that do the work can be, and are, starved of necessary, natural nutrients - all the better to strengthen the need for external interference, which naturally comes with related costs.

The article appears to want to extrapolate from the most favourable case possible, using the resulting figures but without acknowledging any of the factors that made them favourable. Manaus is already on the map of political contentiousness - being the setting for one of the HCQ studies that gave super-high HCQ doses to people in advanced stages of Covid-19 illness, resulting in deaths followed by a community backlash, death threats and court action. The dose has been described in an open letter as “… lethal doses in debilitated patients, many in severe conditions and with comorbidities.”
Link https://conexaopolitica.com.br/ultimas/brazilian-scientists-and-academics-write-an-open-letter-on-the-science-of-the-coronavirus-pandemic/ (Incidentally this letter gives a great criticism of the idea that anyone can assert they are acting in accordance with science).
The dose may not have been intentional or sinister - the scenario of the use of HCQ in Brazil is fraught, suffice it to say the drug was foisted on some of the population with no controls and many people took doses similar to those in the study:

" A Brazilian colleague sent me government documents, including protocols for HCQ administration to indigenous people. The recommended dosages were about as high as those in the ill-fated Manaus clinical trial. I found this document especially disturbing, partly because of its banality. Giving such high doses of HCQ to indigenous patients with preexisting conditions could kill them."

Hydroxychloroquine in Brazil: A Virtual Research Adventure :: Society for...

Even more bizarrely, the above writer accused the Brazilian government of malfeasance towards vulnerable populations during the pandemic - especially the indigenous population in this region, whose consent is unlikely to have been very well informed:
“In early July I read about a Brazilian military medical team that took 13,500 doses of chloroquine to the huge Yanomami indigenous territory in far-northern Brazil. An independent news agency reported, “The operation is intended to counter criticisms that the Bolsonaro government does not do enough to protect indigenous people from the epidemic.” [9]
Before entering the reserve (without the required permission from the Indians), military team members took a Covid-19 test known for its frequent false-negative results in asymptomatic or pre-symptomatic people. They gave out chloroquine in several villages but left the territory after a week—not enough time to follow up. In light of the long history of unauthorized and catastrophic experiments on indigenous people, it is difficult to call this incursion well-conceived or beneficial.”

Manaus doesn’t seem a good place to extrapolate from to the affluent western world.

Just to fish out one or two items from the present piece under discussion:

“Their data show the impact on mortality rates of a largely unmitigated outbreak where even with an estimated 76% of the population being infected, herd immunity was not achieved.”

Has the 76% ‘attack rate’ been got at a stretch over two time periods? It related to an October ‘update’ which is outwith the data period for which comparable death rates are cited (eg UK 620 deaths per million, i.e. about June).

“What the findings of Buss et al. definitively show is that pursuing herd immunity through naturally acquired infection is not a strategy that can be considered.”

This is surely an overstatement of the findings. Arguably the study showed relying on herd immunity is problematic in places like Manaus.

The authors are already public advocates of increased vaccine roll-outs and stronger lockdown. I personally rate Sciencemag as fairly politicized, based on its hosting of counterfactual anti-HCQ narratives.

But ad hom apart, I think a more objective analysis would need to bring in and investigate other aspects of immunity, as there is no doubt some immunity exists in many places (eg see the Yeadon article [1], and the papers referred to there by Le Bert and others on this matter; there’s also the example of the good ship Diamond Princess). Why go to Brazil to ‘find’ non-immunity and then come back and extrapolate it? Why not suggest investigating immunity in the populations of interest ie the target audience?

Still the information on Manaus serves as a warning.

Cheers

[1] https://lockdownsceptics.org/addressing-the-cv19-second-wave.
Mike Yeadon and Barry Thomas
Poor Barry! Who’d be a second author eh? Never get a mention…

[PontiusPrimate]

Excellent comments as usual, ED. I wasn’t aware of the HCQ history in Manaus, and I found the open letter on science and HCQ really thought provoking and well written. It’s clear to me that when the full story on the HCQ debacle comes out, it won’t be a happy one.

@Evvy_dense

These immune systems that do the work can be, and are, starved of necessary, natural nutrients - all the better to strengthen the need for external interference, which naturally comes with related costs.

Incredibly important point. And the basis of the “prepare the terrain” comment that Chris Martensen has been saying in so many of his podcasts over 2020. It’s the reason why everyone should have been given free supplementary vitamin D etc. right from the get-go. @Rippon has been trying to point out the connection between lifestyle, poverty, diet and health for a while. Subjects that most of the media want to ignore because of the indictment of society that is implicit in that criticism. In fact this was one of the nitpicks I had with Dr Simone Gold when she was making a broader point that it’s not race that causes black Americans to be hit harder than white Americans. It might not be race, but it is racism. Anyway. Very important point that is almost never, ever discussed in the context of Covid.

I don’t know the specifics about the hit rate question you ask. To be honest, I’ve not looked at the original research article in detail, only the discussion of it I posted above. It’s worth a look through to try and get to the bottom of that. The link is in the piece posted above. And I do agree that one needs to be careful about trying to extrapolate from one region in the world to another. I have seen other studies, however, that show high percentage numbers of people in closed groups being infected, meaning that if herd immunity (in the sense that the pathogen dies out for want of hosts) is even possible, the percentage of people who need to be infected is high. Probably above 80%. This is another data point that is indicating a similar result. What seems reasonable (from a maths point of view) is that if we were to try and get to that level of infection in the UK, the death toll (even without overwhelming the hospitals etc) would be close to what was initially modeled out by Ferguson (who was clever enough to be a first author!) and his team (bah - second authors onwards!)

Again, I am disconcerted by the two points I raised with Rhis above - we have never had a successful vaccine for a coronavirus prior to this one, and we know that strict herd immunity is at best questionable for other coronaviruses.

Is this one going to be the exception?

Good points - thanks for chiming in!

Cheers

[PatB]

@PontiusPrimate

6 - In the UK we have officially recorded 3.26 million cases. Let’s assume we are way off, and that the number is closer to 15 million people. That still equals about 23%. If the Manaus data is correct, then we would need nearly 3-4 times this number so perhaps 50-60 million people to become infected and then recover (hopefully!)

PP. I fail to understand your reasoning. However here is mine.

1 The figure of 3.26 million cases is just that. Cases. ThePCR test (which I have said before and keep repeating; see the link below) is just that. Cases. It has no correlation in the real world, to sick people or people with symptoms. It also is no measure of those who are immune (by virtue of the PCR test, which completely ignores T cell immunity).

As for “let’s assume the number is 15 million”, it seems (to me at least), that you are adding an assumption, and a pretty big one at that, onto an already false premise!

That said, any argument that depends on the “case” numbers is by default meaningless, unless:
a) the number of cycles is published, and
b) the total number of actual tests is known.

Even with these parameters, relying on the PCR is (IMHO) only pouring fuel on the NWO fire of lockdown, track & trace, and the great?? reset.

This is another destruction of the PCR “test” and includes Kary Mullis.

The PCR Deception

[RhisiartGwilym]

Thanks Pat. (When will this idiot fashion for cluttering up sound-tracks with absolutely unnecessary, seriously-unhelpful shite-muzak die? Soon, I sincerely hope!) It needs saying loud and clear: this ‘test’ is being used falsely to serve an agenda - just as Mullis himself said about the HIV-AIDS scam. Fauci in particular is an obvious racketeer, just as he was over AIDS. And lots of similarly iffy band-waggon-jumpers, particularly the BPh criminals, have piled on to this illicit racket that’s been hitched to the artificial covid panic. I doubt that there’s any large-scale conspiracy, just this chaotic band-waggon carnival (though with smaller real conspiracies scattered about in it, as with the Gatesoids, as a malignant accelerator).

The whole racket needs the brakes clapping on vigorously, and the damned lie of a fearsome global pandemic needs to be rebuffed with determination. There is no huge worldwide medical emergency! A nasty novel illness going through the usual endemicising process, sure. But no emergency. The emergency is being created wilfully within national social structures by the deliberately-destructive effects on people’s livelihoods of the fake ‘protective measures’ being imposed on us - often illegally - and with the by-now evident real protective measures being blatantly ignored, and indeed suppressed! This much I now think is coming pretty clear. As Dolores Cahill asserts: people should be prosecuted for this scam.

Today I go to the local hospital to get an eye-test. I’ll report back on just how busy it really is when I return.

[PontiusPrimate]

Hi Pat

The point I was making is that we are miles off the 80-90% of infections that seem to be needed to have even a chance of herd immunity. And to reach the required level would involve a number of deaths very close to that predicted by Neil Ferguson a couple of weeks into the pandemic, despite all the folk who want to rubbish his numbers.

If you don’t like PCR what would be your preferred metric for measuring infections? Do you have an alternative and more accurate way of measuring how many people have been infected that we could use instead?

As I’ve said many times already, this would be moot if we were making good use of potential treatments. However, it seems we’re not going to do that, so the expected death toll on the path to herd immunity looks grim.

That’s assuming that it’s even possible to reach herd immunity (it may not be). And not counting those who get sick again after “recovering” the first time.

PS: If seems like the primary objection against PCR is that it identifies too many false positives, i.e. it overestimates the true number of infections. Even if that’s true (I think folks worry too much about that, but that’s just me), that makes my argument even stronger. Let’s say that PCR gives a 50% false positive rate - so half that cases are false. That means that instead of 3.25 million cases, there were really only 1.1 million cases. So the herd immunity target of 50-60 million cases is even further away! However you try and slice this, trying to go for natural herd immunity feels like a very bad strategy…

[PontiusPrimate]

@RhisiartGwilym

Today I go to the local hospital to get an eye-test. I’ll report back on just how busy it really is when I return.

They’re unlikely to let you check out the covid ward though… But perhaps you could ask someone about that? It would be interesting…

[Willem]

Interesting thread. Just wanted to make the comment (which Ev_d was hinting at) that immunity (and hence herd immunity) is always presented as a on-off condition. Or, mathematically speaking, a 1-0 law.

From what I’ve understood, the reality much more nuanced; i.e. people have partial or “prior” immunity, depending on their bodies’ ability to recognise viruses or bits of viruses from previous attacks against it.

The dominant narrative seems to be that Covid is a new disease and everyone is considered an empty vessel with no immunity. This assumption has some big consequences in that people are far more scared, and helplessly wait for a vaccine to save them. It also pushes up the figures of likely deaths as in Ferguson’s models.

[Evvy_dense]

Maybe we need two analyses, one with the blind spot (early treatments to prevent those deaths) removed and one without
Or three or four, if you include some measure of initial immunity in the population. Yeadon cites several studies suggesting at least 35% of the population have immunity
(Link https://lockdownsceptics.org/addressing-the-cv19-second-wave/).

He says there were no clinical immunologists on SAGE to tell Ferguson to include this factor. Back in the lull in deaths, Yeadon thought that meant HI had been reached already. Wrong about that - but the principle of some existing immunity is probably still alive. That would bring down the percentage of new people needing to develop natural immunity to something like 50% maybe. If so there’s a chance that could be achieved soon, even discounting the vaccine.
[The vaccine trials were not designed to test for lowering transmission, so that’s more a hope that’s been fed to 45m people to encourage vaccine takeup and peer pressure. Chances are it will probably reduce infections for an unknown time. Vaccine may lower transmission but I’ll leave them out for now].

To side with Pat (PP you’re probably not disagreeing with this), PCR doesn’t measure infections unless the term is redefined - as for Covid, it has been. There are correlates of infectivity and infectiousness, if the threshold for the number of cycles (Ct) was reported along with the testing outcome. Why this was left out is a mystery - I can think of explanations but none of them are good, which to me adds to the air of manipulation.

Seems PCR is what we’re stuck with. It does catch the genuine medical infections too, some unknown fraction or other. Maybe we’re really lucky and the number of ‘real positives’ is a straight percentage of the ‘positives’ counting these magnified fragments of past Covid encounters. I think different countries use different thresholds as cutoff though. (But as more and more people get Covid and recover, will that not generate more false ‘infections’? I feel 'deaths is a better variable to ponder).

What next? This so-called ‘second wave’ may be the last even without the vaccine, with the reservation being that lockdowns don’t seem to alleviate the situation much, and - like holding your breath, you then have to breathe much harder - people then have the need to get back to normal and lose any progress. If we’re ignoring the best (IMO) option - Doctors treat patients! shock - we have

1. hope from the above that we’re near that herd immunity level (may mean ongoing lockdown with whatever effects that’s having, which I think are likely to be dire at societal and population levels)
2. hope ‘the vaccine will save us’ (probably won’t happen quickly enough to prevent tens of thousands more (UK) deaths)

Neither sound great, and they are just hopes!

[Evvy_dense]

Cases are slowing down. Even though we this today on the BBC

Covid-19 in the UK: How many coronavirus cases are there in your area?

I think the BBC gets this from the government’s spin doctors.
I make it about 0.8, based on the fact that over the last 7 days the number of cases reported was 20% less than over the previous 7 days.
It also gives an R of 1.2 for Scotland - patently untrue, it’s about 0.8 there too, and been falling almost every day since the post-Christmas highs.

I noticed that when cases were rising but hadn’t translated into deaths, it was Cases, Cases, Cases in the media. Then deaths started to appear but even when cases slowed down it was Deaths, Deaths, Deaths. Whichever keeps up the fear, never mind accuracy.

Reported deaths are high but I presume likely to start slowing down over the next 7 days, with the already-seen slowing of cases.
But nobody is watching this much - it’s all about the vaccine.

This gushing Guardian article opines it’s really rather wonderful, just like Dunkirk really.

For Britain’s vaccination success, we must thank our universal healthcare system
Gaby Hinsliff

For Britain's vaccination success, we must thank our universal healthcare...

The comments seem to be ‘not free’ - hardly a word of demur in sight.

[PatB]

I’m sorry but you seem to mis the point I was trying to make. It is this.

If you build an argument which starts based on a false premise (PCR “cases”), then adding an assumtion (based on ?) on to that false presmise, you get a result which has almost no basis in reality.

[PontiusPrimate]

Hi @Willem and @Evvy_dense,

Thanks for the comments from both of you.

@Willem

From what I’ve understood, the reality much more nuanced; i.e. people have partial or “prior” immunity, depending on their bodies’ ability to recognise viruses or bits of viruses from previous attacks against it.

So, undoubtedly the situation is not a simple binary one. I am very hopeful that there is a degree of partial immunity from prior exposure to other corona viruses. Lots of people have said something similar, for example Karl Friston on indy Sage, and the Karolinska institute in Sweden as well as the Yeadon reference that ED points out. The problem that I have is that I have seen several studies now, where the actual, real-world level of infections in fairly well studied communities were very high - Manaus, Khayelitsha in south africa, certain parts of India etc. I don’t really know how to interpret this. The paper we are talking about makes the explicit interpretation that the level of infection in Manaus means no one had any prior immunity, so the actual value of that protection was negligible.

So how much can we rely on some level of prior immunity to protect the group? The answer seems unclear at best and perhaps not reliable at all, at worst. The question is how to balance the theoretical possibility of cross-immunity with the real world data showing extremely high infection rates?

Perhaps this is the big difference between individual immunity and herd immunity (in the more narrow technical sense of lack of hosts). Individual immunity is more of a spectrum with variable levels of protection etc, whilst herd immunity is a measure of how well a disease can spread through a population. In that case it makes sense to be very explicit about what kind of immunity we are talking about.

And it also seems to me that it seem very possible that people can gradually ramp up their individual immune response, whilst at the same time the goal of herd immunity stays forever out of reach because those two things are very different.

I suppose that’s exactly what happens with the common cold…

(Or maybe I just don’t understand what I’m talking about. I dropped biology at 13 because I couldn’t draw cells, and never went back! I’m not an authority )

On the subject of PCR,

@Evvy_dense

To side with Pat (PP you’re probably not disagreeing with this), PCR doesn’t measure infections unless the term is redefined - as for Covid, it has been. There are correlates of infectivity and infectiousness, if the threshold for the number of cycles (Ct) was reported along with the testing outcome. Why this was left out is a mystery - I can think of explanations but none of them are good, which to me adds to the air of manipulation.

Yes, you’re right ED. But that’s really not the point I was making. We know that to get real active cases from PCR there is some kind of (possibly unknown) mapping process that needs to happen. From the perspective of the HI discussion, though, the only question that is important is does PCR massively underestimate the true number of infections? That is, is it likely that we have already reached HI levels, despite what the low PCR test percentage suggests?

As I said to Pat above, all the criticism I’ve seen of PCR is that it overestimates the level - i.e. it gives a falsely high number of infections, and the true number is (much?) lower. That makes the problem worse.

Unless the PCR is massively underestimating the true rate of infection (unlikely) and even worse, if it is overestimating the true number of infections (possible) then it means we are only just beginning our journey towards the 80-90% infection level required to reach HI, assuming such a thing is even possible.

That is definitely not a strategy I would feel comfortable actively pursuing… Given the amount of talk about it, this really seems like the final nail in the coffin (bad metaphor!) for me.

If we don’t want to use PCR (although it makes no difference to my argument if we do or not) then we can use antibody studies which show much the same general result.

However we measure it, we are miles away from reaching HI. And the more I think about it, the less clear it becomes to me that we could ever reach it (without a miracle vaccine). This makes sense now, as we never have done so in the past with other coronaviruses, so at least this one feels consistent.

Ok - enough of my waffle. Hopefully the argument I’m presenting here is a little clearer.

Thanks everyone - this discussion is really helping me to think more clearly about what HI is, what individual immunity is and what the connection between them is.

Cheers

[PontiusPrimate]

@PatB

If you build an argument which starts based on a false premise (PCR “cases”), then adding an assumtion (based on ?) on to that false presmise, you get a result which has almost no basis in reality.

Lol! That’s pretty hard for me to argue with, in general

Check out what I wrote above - perhaps it will answer your point, or perhaps I’m still off base.

Cheers
PP

[PontiusPrimate]

Hi @Evvy_dense

would it not be possible for cases to slow and the R number to remain above 1? There are still large number of new cases (depending whether you trust the PCR or not ), so the virus is still clearly spreading. It’s just not spreading as fast as it was… is that right?

One question that is really worth pondering, is that if strict lockdowns etc. really don’t work, then why are the numbers now coming down? It’s not HI.

Hmmm…

[Evvy_dense]

Hi Pontious one

"Hi @Evvy_dense

would it not be possible for cases to slow and the R number to remain above 1? There are still large number of new cases (depending whether you trust the PCR or not ), so the virus is still clearly spreading. It’s just not spreading as fast as it was… is that right?

One question that is really worth pondering, is that if strict lockdowns etc. really don’t work, then why are the numbers now coming down? It’s not HI.

Hmmm…"

I don’t think so. Yes new cases mean it’s spreading but my reading is that R is about acceleration or deceleration. So R above 1 means by definition that on average an infected person transmits to more than one other; isn’t this equivalent to cases accelerating? And R<1 transmit to fewer than 1, ie cases slowing?
That’s what I understand anyway…Cheers